When considering Friction and Bearing on Bolts, what are 'Factor *d' and 'Factor *fcu'?

Solution

Where bolts are solidly cast into concrete - i.e. are set to Non-Adjustable - the bolts can be relied upon to resist shear.

In this case, the design may be based on effective bearing length in concrete of 3d and an average bearing stress of 2 fcu.  For more about this see the related article linked at the bottom of this article.

Where bolts are not solidly cast into concrete i.e. set to are Adjustable, some allowance can be made for a reduction of the bearing on the bolts capacity via the factors "Factor * d" , which adjusts the bolt bearing length, and "Factor * fcu" which adjusts the concrete bearing stress.  The default value of both factors is 1.0.

• Factors of 3 and 2 respectively provide the same resistance as if the bolts were solidly cast (Non-Adjustable) - this would be un-conservative.
• Factors of 0 and 0 assume the bolts provide no shear resistance  - this would be conservative.

The values to use for your connection is a matter for your engineering judgement - we cannot provide specific advice on the values to be used.